Tomas Vondra <tv@fuzzy.cz> writes:
> Well, until this point we've discussed failure cases involving 'AND'
> conditions. What about 'OR' conditions? I think the current optimizer
> computes the selectivity as 's1+s2 - s1*s2' (at least that's what I
> found in backend/optimizer/path/clausesel.c:630).
If you can solve the AND case, the OR case falls out of that. Just
replace s1*s2 with a more accurate AND calculation.
regards, tom lane